Compilation notes

Ruby, any version between
1.9 and 2.3. Ruby is only necessary for the building process, it is
not necessary

mruby. However, be warned that `QSoas` will
need at least version `1.3.0` to compile, but will crash due to
bugs in mruby for versions `1.3.0` and
`1.4.0`. While hopefully `1.4.1` should fix this problem, you
should get a version between git commits
7450a774 and
afa5380, or
posterior to
55431b4.